v3.25.2
Fair Value Measurements - Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value $ 17,077 $ 16,182
Fair value of asset 29,841 28,628
Separate accounts 991 952
Top Hat savings plan mutual funds and common equity (included in Other assets) 94 87
Short-Term Investments 100 298
Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 8,987 8,380
States, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 4,708 4,721
Government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 2,447 2,274
Asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 732 551
United States government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 183 226
Foreign government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 20 30
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 183 226
Fair value of asset 11,705 11,447
Top Hat savings plan mutual funds and common equity (included in Other assets) 94 87
Short-Term Investments 100 298
Level 1 | Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 1 | States, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 1 | Government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 1 | Asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 1 | United States government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 183 226
Level 1 | Foreign government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 16,894 15,956
Fair value of asset 18,136 17,181
Top Hat savings plan mutual funds and common equity (included in Other assets) 0 0
Short-Term Investments 0 0
Level 2 | Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 8,987 8,380
Level 2 | States, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 4,708 4,721
Level 2 | Government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 2,447 2,274
Level 2 | Asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 732 551
Level 2 | United States government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 2 | Foreign government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 20 30
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Fair value of asset 0 0
Top Hat savings plan mutual funds and common equity (included in Other assets) 0 0
Short-Term Investments 0 0
Level 3 | Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 3 | States, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 3 | Government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 3 | Asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 3 | United States government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Level 3 | Foreign government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fixed maturities, at fair value 0 0
Equity securities | Common equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 11,309 10,836
Equity securities | Nonredeemable preferred equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 340 349
Equity securities | Level 1 | Common equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 11,309 10,836
Equity securities | Level 1 | Nonredeemable preferred equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 0 0
Equity securities | Level 2 | Common equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 0 0
Equity securities | Level 2 | Nonredeemable preferred equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 340 349
Equity securities | Level 3 | Common equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 0 0
Equity securities | Level 3 | Nonredeemable preferred equities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair value of asset 0 0
Separate accounts taxable fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Separate accounts 921 876
Separate accounts taxable fixed maturities | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Separate accounts 19 0
Separate accounts taxable fixed maturities | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Separate accounts 902 876
Separate accounts taxable fixed maturities | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Separate accounts $ 0 $ 0